Line data    Source code

       1             : /* Find the debuginfo file for a module from its build ID.
       2             :    Copyright (C) 2007, 2009, 2014 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #include "libdwflP.h"
      30             : #include <unistd.h>
      31             : 
      32             : 
      33             : int
      34          88 : dwfl_build_id_find_debuginfo (Dwfl_Module *mod,
      35             :                               void **userdata __attribute__ ((unused)),
      36             :                               const char *modname __attribute__ ((unused)),
      37             :                               Dwarf_Addr base __attribute__ ((unused)),
      38             :                               const char *file __attribute__ ((unused)),
      39             :                               const char *debuglink __attribute__ ((unused)),
      40             :                               GElf_Word crc __attribute__ ((unused)),
      41             :                               char **debuginfo_file_name)
      42             : {
      43          88 :   int fd = -1;
      44             : 
      45             :   /* Are we looking for a separate debug file for the main file or for
      46             :      an alternate (dwz multi) debug file?  Alternatively we could check
      47             :      whether the dwbias == -1.  */
      48          88 :   if (mod->dw != NULL)
      49             :     {
      50             :       const void *build_id;
      51             :       const char *altname;
      52           6 :       ssize_t build_id_len = INTUSE(dwelf_dwarf_gnu_debugaltlink) (mod->dw,
      53             :                                                                    &altname,
      54             :                                                                    &build_id);
      55           6 :       if (build_id_len > 0)
      56           6 :         fd = __libdwfl_open_by_build_id (mod, true, debuginfo_file_name,
      57             :                                          build_id_len, build_id);
      58             : 
      59           6 :       if (fd >= 0)
      60             :         {
      61             :           /* We need to open an Elf handle on the file so we can check its
      62             :              build ID note for validation.  Backdoor the handle into the
      63             :              module data structure since we had to open it early anyway.  */
      64           1 :           Dwfl_Error error = __libdw_open_file (&fd, &mod->alt_elf,
      65             :                                                 true, false);
      66           1 :           if (error != DWFL_E_NOERROR)
      67           0 :             __libdwfl_seterrno (error);
      68             :           else
      69             :             {
      70             :               const void *alt_build_id;
      71           1 :               ssize_t alt_len = INTUSE(dwelf_elf_gnu_build_id) (mod->alt_elf,
      72             :                                                                 &alt_build_id);
      73           1 :               if (alt_len > 0 && alt_len == build_id_len
      74           1 :                   && memcmp (build_id, alt_build_id, alt_len) == 0)
      75           1 :                 return fd;
      76             :               else
      77             :                 {
      78             :                   /* A mismatch!  */
      79           0 :                   elf_end (mod->alt_elf);
      80           0 :                   mod->alt_elf = NULL;
      81           0 :                   close (fd);
      82           0 :                   fd = -1;
      83             :                 }
      84           0 :               free (*debuginfo_file_name);
      85           0 :               *debuginfo_file_name = NULL;
      86           0 :               errno = 0;
      87             :             }
      88             :         }
      89           5 :       return fd;
      90             :     }
      91             : 
      92             :   /* We don't even have the Dwarf yet and it isn't in the main file.
      93             :      Try to find separate debug file now using the module build id.  */
      94             :   const unsigned char *bits;
      95             :   GElf_Addr vaddr;
      96             : 
      97          82 :   if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0)
      98          82 :     fd = __libdwfl_open_mod_by_build_id (mod, true, debuginfo_file_name);
      99          82 :   if (fd >= 0)
     100             :     {
     101             :       /* We need to open an Elf handle on the file so we can check its
     102             :          build ID note for validation.  Backdoor the handle into the
     103             :          module data structure since we had to open it early anyway.  */
     104           8 :       Dwfl_Error error = __libdw_open_file (&fd, &mod->debug.elf, true, false);
     105           8 :       if (error != DWFL_E_NOERROR)
     106           0 :         __libdwfl_seterrno (error);
     107           8 :       else if (likely (__libdwfl_find_build_id (mod, false,
     108             :                                                 mod->debug.elf) == 2))
     109             :         {
     110             :           /* Also backdoor the gratuitous flag.  */
     111           8 :           mod->debug.valid = true;
     112           8 :           return fd;
     113             :         }
     114             :       else
     115             :         {
     116             :           /* A mismatch!  */
     117           0 :           elf_end (mod->debug.elf);
     118           0 :           mod->debug.elf = NULL;
     119           0 :           close (fd);
     120           0 :           fd = -1;
     121             :         }
     122           0 :       free (*debuginfo_file_name);
     123           0 :       *debuginfo_file_name = NULL;
     124           0 :       errno = 0;
     125             :     }
     126          74 :   return fd;
     127             : }
     128             : INTDEF (dwfl_build_id_find_debuginfo)